Biomolecular image sensor and method thereof for detecting biomolecule

ABSTRACT

The invention provides a biomolecular image sensor with a plurality of microstructures repeatedly arranged on a surface of an image sensing element, and method thereof for detecting biomolecule.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of U.S. provisional application No.63/255,446, filed on Oct. 14, 2021, the content of which is incorporatedherein in its entirety by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a biomolecular image sensor and methodthereof for detecting biomolecule, and more particularly to abiomolecular image sensor with a plurality of microstructures repeatedlyarranged on a surface of an image sensing element, and method thereoffor detecting biomolecule.

2. The Prior Art

Enzyme-linked immunosorbent assay (ELISA) or enzyme-linked immunoassay(EIA) is the specific antigen-antibody reaction tests. The specificbinding properties between antigens and antibodies are used to detectthe molecules in samples. The presence of specific antigens orantibodies may be shown by the color reaction with enzymes. Quantitativeanalysis may be carried out by the depth of color to achieve thedetection and screening.

Biochips are micro devices that use biological materials on a substrateto produce specific biochemical reactions with the biomolecules, and maybe quantified by a highly sensitive detection system. Biochips providefast, accurate, and low cost bioanalytical testing capabilities.Biochips are basically miniaturized substrates that may perform hundredsor thousands of biochemical reactions simultaneously.

However, traditional biochemical tests such as on tissue sectionsrequire large and expensive equipment to receive optical or electronicsignals for analyzing the status of biochemical molecular reactions, forexample, observing with microscopes and capturing images with additionalphoto equipment for further analysis, which require time and manualoperations. On the other hand, traditional biochips have to beadditionally equipped with other expensive and large image capturesystems or equipment to detect and capture the luminescent images of thebiochips after the biochemical detection process for subsequentanalysis. Further, traditional ELISA has to be equipped with an ELISAreader to detect the absorbance in each well of the micro-well plateafter the operation with ELISA kit for quantification.

With the increasing popularity of the point of care testing (POCT), apersonalized health test with a short analysis time and simpleoperation, it is necessary to develop a more sensitive and simplerdetection device and method to overcome the problems from largeequipment and complex biochemical detection processes in traditionalbiomolecule detection methods.

SUMMARY OF THE INVENTION

One objective of the present invention is to provide a biomolecularimage sensor, comprising: an image sensing element, containing aplurality of unit pixels disposed in an array on a substrate, whereineach of the plurality of unit pixels contains at least one photoelectricconversion element, the photoelectric conversion element receives anincident light to generate electrons, and a surface of the image sensingelement receiving the incident light is defined as a light receivingsurface; and a microstructure layer, disposed on the light receivingsurface of the image sensing element and having a plurality ofmicrostructures arranged in a specific shape repeatedly, wherein each ofthe plurality of microstructures corresponds to at least one unit pixel.

In the preferred embodiment of the present invention, the microstructurelayer is an array formed by a plurality of inverted pyramidal orhoneycomb microstructures.

In the preferred embodiment of the present invention, each of themicrostructures is formed on the image sensor element byphotolithography process or imprint lithography process.

The further objective of the present invention is to provide abiomolecular image sensor, comprising: an image sensing element,containing a plurality of unit pixels disposed in an array on asubstrate, wherein each of the plurality of unit pixels contains atleast one photoelectric conversion element, the photoelectric conversionelement receives an incident light to generate electrons, and a surfaceof the image sensing element receiving the incident light is defined asa light receiving surface; and a microstructure layer, disposed on thelight receiving surface of the image sensing element and being an arrayformed by a plurality of microlenses, wherein a plurality ofmicrostructures are formed between the plurality of microlenses, andeach of the plurality of microstructures corresponds to at least oneunit pixel.

In the preferred embodiment of the present invention, the biomolecularimage sensor further comprises at least one readout circuit coupled tothe unit pixels, and the readout circuit generates a voltage signalbased on the number of the electrons.

In the preferred embodiment of the present invention, each of themicrolenses is provided to accommodate at least one biomolecule.

In the preferred embodiment of the present invention, the incident lightis a light emitted by a fluorescent marker or a chemiluminescent markeron the biomolecule.

In the preferred embodiment of the present invention, the biomolecularimage sensor further comprises a carrier carrying the biomolecule, andthe carrier is accommodated in the microstructure, and the carrier maybe a microparticle. Further, one microstructure accommodates one carrierchemically bonded with multiple biomolecules.

In the preferred embodiment of the present invention, the bottomportions and the side portions of the microstructures are composed ofdifferent materials, and each of the microlenses is formed on the imagesensor element by photolithography process or imprint lithographyprocess.

The other objective of the present invention is to provide a method ofdetecting a biomolecule, comprising: (a) providing the biomolecularimage sensor; (b) accommodating the biomolecule in a sample in each ofthe plurality of microstructures; (c) detecting an incident light ineach of the plurality of microstructures by each of the plurality ofunit pixels; (d) generating electrons from the incident light detectedby each of the plurality of unit pixels by the photoelectric conversionelement; (e) generating a voltage signal based on a number of theelectrons by a readout circuit coupled to each of the plurality of unitpixels; and (f) analyzing a presence and/or a concentration of thebiomolecule based on the voltage signal; wherein, a fluorescent markeror a chemiluminescent marker is added on the biomolecule before or after(b), and the incident light comprises a light emitted by the fluorescentmarker or the chemiluminescent marker.

The present invention is a completely innovative image sensor fordetecting biomolecules prepared by a semiconductor process. The imagesensor of the present invention, which is smaller than a coin, maydirectly detect the presence of specific biomolecules in samples andquantify concentration thereof, but does not require additional largeequipment.

On the other hand, compared with the traditional biochip, the presentinvention does not require additional image capture system or equipment.That is, the biomolecular image sensor of the present invention providesthe functions of biological or chemical analysis and image capture andinterpretation. That is, the detection process may be directly operatedon the biomolecule image sensor of the present invention, andcorresponding detection results may be obtained in real time.

On the other hand, compared with the traditional methods of quantifyingbiomolecules, the biomolecule image sensor of the present inventionindependently detects the incident light in the correspondingmicrostructure through each unit pixel, and compares each measuredsignal readout with the thresholds independently, and therefore, evenwhen the concentration of the biomolecules in the sample is extremelylow, the presence and intensity of chemiluminescent or fluorescentsignals of the biomolecules would still be accurately interpreted, so asto increase the detection sensitivity.

Further, because the microstructure in the biomolecule image sensor ofthe present invention enables the biomolecules to be dispersed evenly onthe light receiving surface, the photoelectric conversion element wouldeasily determine the incident light really from the luminescent orfluorescent markers on the biomolecules. The biomolecule image sensor ofthe present invention provides the quantitative mode of analogcolorimetric method and digital method, and could be switched accordingto different concentrations of biomolecules, so as to maximize thedetection range.

In order to enable one with ordinary skill in the art to understand thepurpose, features, and functions of the present invention, the inventionis described in detail below by means of the following specificembodiments and with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section view of the biomolecular image sensoraccording to one embodiment of the present invention.

FIG. 2 shows a schematic view of inverted pyramidal microstructures ofthe biomolecular image sensor according to another embodiment of thepresent invention.

FIG. 3 shows a schematic view of honeycomb microstructures of thebiomolecular image sensor according to another embodiment of the presentinvention.

FIG. 4A shows a schematic view of the biomolecular image sensoraccording to another embodiment of the present invention, wherein themicrostructure layer is an array formed by a plurality of microlensesand one photoelectric conversion element corresponds to fourmicrolenses.

FIG. 4B shows a cross-sectional view of the biomolecular image sensorshown in FIG. 4A.

FIG. 5 shows a schematic view of the biomolecular image sensor accordingto another embodiment of the present invention, wherein themicrostructure layer is an array formed by a plurality of microlensesand one photoelectric conversion element corresponds to themicrostructure formed by four microlenses.

FIG. 6 shows a schematic view of the biomolecular image sensor accordingto another embodiment of the present invention, wherein themicrostructure layer is an array formed by a plurality of microlensesand one photoelectric conversion element corresponds to one microlens.

FIG. 7A shows a flowchart of the method of detecting biomoleculesthrough the biomolecular image sensor according to one embodiment of thepresent invention.

FIG. 7B shows a flowchart of the method of detecting biomoleculesthrough the biomolecular image sensor according to another embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiments of the present invention are further described with thefollowing drawings. The following embodiments are given to illustratethe present invention and are not intended to limit the scope of thepresent invention, and one with ordinary skill in the art may make somemodifications and refinements without departing from the spirit andscope of the present invention. Therefore, the scope of the presentinvention is defined by the scope of the appended claims.

The terms used herein are only for describing the embodiments, and arenot intended to limit the present invention. Unless otherwise defined,the terms have meanings commonly understood by one with ordinary skillin the art to which the present invention belongs. As used herein, thesingular forms “a” and “the” are intended to include the plural forms aswell, unless the context clearly indicates otherwise. As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Similarly, when an element is referred to be “on” another element, itwould be understood that the element may be directly on the otherelement or intermediate elements may be present. In contrast, the term“directly” represents that there is no intermediate element. The term“comprising” used herein should be understood to indicate the presenceof stated features, integers, steps, operations, elements, and/orcomponents, but not exclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or any combination thereof.

According to the present invention, the operating procedures andparameter conditions for enzyme-linked immunosorbent assay (ELISA) arewithin the professional literacy and routine techniques of one withordinary skill in the art.

According to the present invention, the fluorescent molecules may be,but not limited to, FITC, HEX, FAM, TAMRA, Cy3, Cy5, quantum dot, or thelike, and may be used with a quencher dye.

FIG. 1 shows a biomolecular image sensor 100 according to one embodimentof the present invention. As shown in FIG. 1 , the biomolecule imagesensor 100 of the present invention comprises: an image sensing element10 and a microstructure layer 20, and may further comprise at least onereadout circuit; wherein, the image sensing element 10 may contain aplurality of unit pixels 11 disposed in an array on a substrate;further, the microstructure layer 20 may have a plurality ofmicrostructures 21 repeatedly arranged in a specific shape, and mayaccommodate a biomolecule A, or a carrier 22 carrying with a biomoleculeA.

More specifically, the image sensing element 10 in the biomolecularimage sensor 100 according to the present invention may be aback-illuminated complementary metal-oxide-semiconductor (CMOS) imagesensor or a front-illuminated CMOS image sensor; however, the presentinvention is not limited thereto.

In the embodiments of the present invention, each of the unit pixels 11may include at least one photoelectric conversion element, wherein thephotoelectric conversion element may generate electrons after receivingan incident light, and the photoelectric conversion element alsocontains the ability to accumulate the above-mentioned electrons;however, the present invention is not limited to thereto.

Further, the photoelectric conversion element may be an element thatgenerates and accumulates electrons corresponding to the incident light.For example, the photoelectric conversion element may be a photodiode, aphoto transistor, a photo gate, a pinned photo diode (PPD), an avalanchephotodiode (APD), a single-photon avalanche diode (SPAD), aphotomultiplier tube (PMT), or any combination thereof.

In the embodiments of the present invention, a surface of the imagesensing element 10 receiving the incident light may be defined as alight receiving surface, and the microstructure layer 20 may be disposedon the light receiving surface. In the preferred embodiments of thepresent invention, each of the microstructures 21 in the microstructurelayer 20 may correspond to the unit pixel 11 respectively. In this way,since the microstructures 21 have a corresponding relationship with theunit pixels 11, the photoelectric conversion elements in the unit pixels11 may receive the incident light corresponding to the microstructures21.

The biomolecular image sensor 100 of the present invention may be formedby a semiconductor process. More specifically, the microstructures 21may be formed on the image sensing element 10 by photolithographyprocess or imprint lithography process, and not just general by surfacetreatment or coatings.

In the embodiments of the present invention, the readout circuits may becoupled to the unit pixels 11 and generate a voltage signal, which isused as the signal readout, according to the number of the electronsgenerated after the photoelectric conversion element receives theincident light.

The biomolecular image sensor 100 of the present invention is notlimited to any specific applications. In one preferred embodiment, thebiomolecule image sensor 100 of the present invention is used forbiological or chemical analysis, such as detecting the presence and/orconcentration of a biomolecule A in a sample. That is, the incidentlight may be a light emitted by a marker, a fluorescent marker, areporter marker, or a chemiluminescent marker of the biomolecule A. Inother words, the presence and concentration of the biomolecule A may beanalyzed by detecting the markers. More specifically, when thebiomolecule image sensor 100 of the present invention is used to detectthe biomolecule A, in the biological or chemical analysis process, thebiomolecule A may undergo luminescence reaction with other molecules andemit an incident light such as chemiluminescence or fluorescence.Further, the biomolecule A may be a protein, a peptide, an antibody, anucleic acid, or the like.

More specifically, the microstructures 21 may be disposed to accommodatethe biomolecules A, and the biomolecules A in the sample may bedispersed in a plurality of the microstructures 21. Since the singlemicrostructure 21 corresponds to the single unit pixel 11, thephotoelectric conversion element in the single unit pixel 11 would onlyreceive the light emitted by the biomolecules A in the singlemicrostructure 21. Therefore, the sensitivity of detecting the specificbiomolecule A in the sample would be improved.

Further, the biomolecule image sensor 100 of the present invention maybe used with a carrier 22 for carrying the biomolecule A, so that thebiomolecule A may be more easily accommodated in the microstructures 21,and the luminescence reaction of the biomolecule A may be easilyperformed. For example, the carrier 22 may be a microparticle, and themicroparticle may be used for performing ELISA. The biomolecule A islinked on the microparticle for performing the luminescence reaction togenerate a chemiluminescence, and the chemiluminescence is the incidentlight received by the photoelectric conversion element in the unit pixel11. The biomolecule A such as an antibody may be linked to themicroparticle by forming an amide bond through the EDC/NHS reaction.

More specifically, the microparticle is preferably a magnetic bead with1 to 3 µm diameter. The magnetic bead may be prepared by magneticmaterials of magnetic elements such as Fe, Ni, Co, ferromagnetic alloyssuch as Nb-Fe-B, or iron oxides such as Fe₃O₄, Fe₂O₃, FeO.Alternatively, the microparticle may also be prepared by non-magneticmaterials such as Au, sepharose, polystyrene, and SiO₂.

More specifically, the single microstructure 21 has to accommodate onlyone carrier 22 as much as possible, so the width/diameter andheight/depth of the microstructures 21 have to match the carrier 22.More specifically, the diameter of the microstructure is preferably 1.3to 1.8 times larger than the diameter of the microparticle, the depth ispreferably 1.2 to 1.3 times larger than the diameter of themicroparticle, and the aspect ratio is preferably 1 to 1.2 times. Forexample, when the carrier 22 is a microparticle with 2 µm diameter, themicrostructures 21 may be grooves with 2.5 to 3 µm diameter and 2.5 µmdepth, and the spacing between each microstructure is 2-3 µm. To avoidthe molecular forces between the carriers 22 to cause them stack on eachother and fail to disperse into a single one, which further causes thesingle carrier 22 difficult to accommodate in one single microstructure21, surfactant, external magnetic field, or vibration to destroy theforce between the carriers 22 may be used to improve the degree ofdispersion thereof.

Alternatively, the biomolecule A may be detected by an antibody oraptamer labeled with a fluorescent molecule. A radiated light isgenerated by irradiating excitation light with a specific wavelength,and the radiated light is the incident light received by thephotoelectric conversion element in the unit pixel 11. Antibodies oraptamers labeled with different fluorescent molecules may be containedon the same carrier 22, so that the detection of various targetbiomolecules may be performed on the same sample during one singledetection. Further, a CMOS image sensor with RGB technology may be usedfor antibodies or aptamers containing multiple fluorescent labels.

In the biomolecular image sensor 100 of the present invention, thebottom portions and the side portions of the microstructures 21 may becomposed of the same or different materials. For example, a surface ofthe microstructures 21 in contact with the light receiving surface(i.e., the bottom portions) may be composed of light-transmittingmaterials such as SiO₂, while a surface of the microstructures 21 not incontact with the light receiving surface (i.e., the side portions) maybe composed of opaque materials such as silicon. Alternatively, thebottom portions and the side portions of the microstructures 21 may bothbe composed of SiO₂.

Alternatively, the microstructures 21 may be implemented in differentembodiments to allow the carriers 22 to be more easily accommodated inthe microstructures 21, taking into account the influence of airpressure or hydrodynamics on the carriers 22 during operation.

For example, FIG. 2 shows a biomolecule image sensor 100A according toanother embodiment of the present invention. The microstructure layer20A may be an array formed by a plurality of inverted pyramidalmicrostructures 21A, which facilitates the gathering of the incidentlight, and the inverted pyramidal microstructures 21A are preferablywith 2.5 µm length and width. Alternatively, FIG. 3 shows a biomoleculeimage sensor 100B according to another embodiment of the presentinvention. The microstructure layer 20B may be an array formed by aplurality of honeycomb microstructures 21B. The most densely distributedwithout gaps between the honeycomb microstructures 21B is favorable forthe carrier 22 to be evenly accommodated therein. The honeycombmicrostructures 21B are preferably with 1.55 µm length and 2.5 µm depth.

FIGS. 4A and 4B show a biomolecule image sensor 200 according to anotherembodiment of the present invention. As shown in FIGS. 4A and 4B, in thebiomolecular image sensor 200 of the present invention, themicrostructure layer 40 may be an array formed by a plurality ofmicrolenses 42, wherein a plurality of microstructures 41 are formedbetween the microlenses 42 to accommodate the biomolecule A or thecarrier 22 carrying the biomolecule A. The microlenses 42 and the unitpixels 11 may be correspondingly arranged in different ways.

More specifically, as shown in FIG. 4A, on the unit pixels 11, fourmicrolenses 42 may be arranged corresponding to one single unit pixel11, wherein the area of the unit pixel 11 may be greater than or equalto the area surrounded by the four microlenses 42. Alternatively, asshown in FIG. 5 , in the biomolecule image sensor 200A of the presentinvention, the area of the unit pixel 11A may be smaller than the areasurrounded by the four microlenses 42, and the microstructure 41 formedby the four microlenses 42 is arranged corresponding to the unit pixel11A. Alternatively, as shown in FIG. 6 , in the biomolecule image sensor200B of the present invention, each microlens 42 may be arrangedcorresponding to one single unit pixel 11B respectively.

As shown in FIGS. 7A and 7B, the method of detecting a biomolecule in asample by the biomolecule image sensor of the present invention may beas following. A fluorescent marker or a chemiluminescent marker is addedto the biomolecules in the sample through biological or chemicalanalysis such as ELISA, and the biomolecules are accommodated in themicrostructures (S11). The incident light in one single microstructureis detected by the unit pixels respectively (S12), wherein the incidentlight includes the lights emitted by the fluorescent maker or thechemiluminescent marker of the biomolecule. Electrons are generated fromthe incident light received by each of the unit pixels through thephotoelectric conversion element (S13). A voltage signal is generatedaccording to the number of the electrons through the readout circuits(S14). The presence and/or concentration of the biomolecule are thenanalyzed according to the voltage signal.

Alternatively, when the biomolecule image sensor of the presentinvention is used to detect a biomolecule in a sample, the biomoleculecontaining fluorescent makers or chemiluminescent markers may also beplaced on a substrate such as a glass slide, traditional biochips, orthe like. The substrate is then placed on the biomolecule image sensorof the present invention, so that the unit pixels would detect anincident light from the corresponding position respectively. Then,electrons are also generated from the incident light through thephotoelectric conversion element, and a voltage signal, which is used asthe signal readout, is generated according to the number of theelectrons through the readout circuits. The presence and/orconcentration of the biomolecule are then analyzed according to thevoltage signal.

When the biomolecule image sensor of the present invention is used toanalyze the presence and/or concentration of the biomolecule, thequantification thereof may be not only performed by analog colorimetricmethod, that is, the incident light in one single microstructurereceived by the unit pixels is one single readout to determine thepresence of the biomolecule (S151) or further compare with the standardcurve for obtaining the concentration of the biomolecule (S161), butalso by digital method, that is, according to the predeterminedthreshold (S152), the unit pixels with the signal readout exceeding thethreshold are defined as 1 (S153) and the unit pixels with the signalreadout not exceeding the threshold are defined as 0 (S154), and thenumber of unit pixels defined as 1 is calculated and compared with thestandard curve (S162) to obtain the concentration of the biomoleculemore accurately.

Further, traditional ELISA utilizes large and expensive equipment toreceive optical or electrical signals after performing complexbiochemical detection procedures to analyze the status of biochemicalmolecular reactions. The present invention is a completely innovativeimage sensor for detecting biomolecules prepared by a semiconductorprocess. The image sensor of the present invention, which is smallerthan a coin, may directly detect the presence of specific biomoleculesin samples and quantify concentration thereof, but does not requireadditional large equipment.

On the other hand, compared with the traditional biochip, the presentinvention does not require additional image capture system or equipment.That is, the biomolecular image sensor of the present invention providesthe functions of biological or chemical analysis and image capture andinterpretation. That is, the detection process may be directly operatedon the biomolecule image sensor of the present invention, andcorresponding detection results may be obtained in real time.

On the other hand, when quantifying biomolecular images by traditionalmethods, such as observation with a microscope, if the concentration ofthe biomolecules is extremely low, the biomolecules directly placed onthe surface of the glass slide would distribute extremely uneven,resulting that only a small part of the area (i.e., the unit pixel)contains chemiluminescent or fluorescent signals, and therefore, thepresence and intensity of the optical signals cannot be effectivelyinterpreted within the overall field of view, so as to decrease thedetection sensitivity. However, the biomolecule image sensor of thepresent invention independently detects the incident light in thecorresponding microstructure through each unit pixel, and compares eachmeasured signal readout with the thresholds independently, andtherefore, even when the concentration of the biomolecules in the sampleis extremely low, the presence and intensity of chemiluminescent orfluorescent signals of the biomolecules would still be accuratelyinterpreted, so as to increase the detection sensitivity. Further,because the microstructure in the biomolecule image sensor of thepresent invention enables the biomolecules to be dispersed evenly on thelight receiving surface, the photoelectric conversion element wouldeasily determine the incident light really from the luminescent orfluorescent markers on the biomolecules. The biomolecule image sensor ofthe present invention provides the quantitative mode of analogcolorimetric method and digital method, and could be switched accordingto different concentrations of biomolecules, so as to maximize thedetection range.

What is claimed is:
 1. A biomolecular image sensor, comprising: an imagesensing element, containing a plurality of unit pixels disposed in anarray on a substrate, wherein each of the plurality of unit pixelscontains at least one photoelectric conversion element, thephotoelectric conversion element receives an incident light to generateelectrons, and a surface of the image sensing element receiving theincident light is defined as a light receiving surface; and amicrostructure layer, disposed on the light receiving surface of theimage sensing element and having a plurality of microstructures arrangedin a specific shape repeatedly, wherein each of the plurality ofmicrostructures corresponds to at least one unit pixel.
 2. Thebiomolecular image sensor according to claim 1, wherein themicrostructure layer is an array formed by a plurality of invertedpyramidal or honeycomb microstructures.
 3. The biomolecular image sensoraccording to claim 1, wherein each of the microstructures is formed onthe image sensor element by photolithography process or imprintlithography process.
 4. The biomolecular image sensor according toclaims 1, wherein each of the microstructures is provided to accommodateat least one biomolecule.
 5. The biomolecular image sensor according toclaim 4, wherein the incident light is a light emitted by a fluorescentmarker or a chemiluminescent marker on the biomolecule.
 6. Thebiomolecular image sensor according to claim 5, further comprising acarrier carrying the biomolecule, and the carrier is accommodated in themicrostructure.
 7. The biomolecular image sensor according to claim 6,wherein the carrier is a microparticle.
 8. A method of detecting abiomolecule, comprising: (a) providing the biomolecular image sensoraccording to claims 1; (b) accommodating the biomolecule with afluorescent marker or a chemiluminescent marker in each of the pluralityof microstructures; (c) detecting an incident light in each of theplurality of microstructures by each of the plurality of unit pixels,wherein the incident light comprises a light emitted by the fluorescentmarker or the chemiluminescent marker; (d) generating electrons from theincident light detected by each of the plurality of unit pixels by thephotoelectric conversion element; (e) generating a voltage signal basedon a number of the electrons by a readout circuit coupled to each of theplurality of unit pixels; and (f) analyzing a concentration of thebiomolecule based on the voltage signal.
 9. A biomolecular image sensor,comprising: an image sensing element, containing a plurality of unitpixels disposed in an array on a substrate, wherein each of theplurality of unit pixels contains at least one photoelectric conversionelement, the photoelectric conversion element receives an incident lightto generate electrons, and a surface of the image sensing elementreceiving the incident light is defined as a light receiving surface;and a microstructure layer, disposed on the light receiving surface ofthe image sensing element and being an array formed by a plurality ofmicrolenses, wherein a plurality of microstructures are formed betweenthe plurality of microlenses, and each of the plurality ofmicrostructures corresponds to at least one unit pixel.
 10. Thebiomolecular image sensor according to claim 9, wherein each of theplurality of microlenses is formed on the image sensor element byphotolithography process or imprint lithography process.
 11. Thebiomolecular image sensor according to claims 9, wherein each of themicrostructures is provided to accommodate at least one biomolecule. 12.The biomolecular image sensor according to claim 11, wherein theincident light is a light emitted by a fluorescent marker or achemiluminescent marker on the biomolecule.
 13. The biomolecular imagesensor according to claim 12, further comprising a carrier carrying thebiomolecule, and the carrier is accommodated in the microstructure. 14.The biomolecular image sensor according to claim 13, wherein the carrieris a microparticle.
 15. A method of detecting a biomolecule, comprising:(a) providing the biomolecular image sensor according to claims 9; (b)accommodating the biomolecule in a sample in each of the plurality ofmicrostructures; (c) detecting an incident light in each of theplurality of microstructures by each of the plurality of unit pixels;(d) generating electrons from the incident light detected by each of theplurality of unit pixels by the photoelectric conversion element; (e)generating a voltage signal based on a number of the electrons by areadout circuit coupled to each of the plurality of unit pixels; and (f)analyzing a presence and/or a concentration of the biomolecule based onthe voltage signal; wherein, a fluorescent marker or a chemiluminescentmarker is added on the biomolecule before or after (b), and the incidentlight comprises a light emitted by the fluorescent marker or thechemiluminescent marker.